Premium
Diverse organization of immunoglobulin VH gene loci in a primitive vertebrate.
Author(s) -
Kokubu F.,
Litman R.,
Shamblott M. J.,
Hinds K.,
Litman G. W.
Publication year - 1988
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1988.tb03215.x
Subject(s) - biology , vertebrate , genetics , gene , immunoglobulin heavy chain , evolutionary biology , antibody , computational biology
The immunoglobulin (Ig) heavy chain variable (VH) gene family of Heterodontus francisci (horned shark), a phylogenetically distant vertebrate, is unique in that VH, diversity (DH), joining (JH) and constant region (CH) gene segments are linked closely, in multiple individual clusters. The V regions of 12 genomic (liver and gonad) DNA clones have been sequenced completely and three organization patterns are evident: (i) VH‐D1‐D2‐JH‐CH with unique 12/22 and 12/12 spacers in the respective D recombination signal sequences (RSSs); VH and JH segments have 23 nucleotide (nt) spacers, (ii) VHDH‐JH‐CH, an unusual germline configuration with joined VH and DH segments and (iii) VHDHJH‐CH, with all segmental elements being joined. The latter two configurations do not appear to be pseudogenes. Another VH‐D1‐D2‐JH‐CH gene possesses a D1 segment that is flanked by RSSs with 12 nt spacers and a D2 segment with 22/12 spacers. Based on the comparison of spleen, VH+ cDNA sequences to a germline consensus, it is evident that both DH segments as well as junctional and N‐type diversity account for Ig variability. In this early vertebrate, the Ig genes share unique properties with higher vertebrate T‐cell receptor as well as with Ig and may reflect the structure of a common ancestral antigen binding receptor gene.